java.lang.AbstractMethodError
   at org.netbeans.modules.maven.NbMavenProjectImpl$OtherRootsVisitor.preVisitDirectory(NbMavenProjectImpl.java:733)
   at org.netbeans.modules.maven.NbMavenProjectImpl$OtherRootsVisitor.preVisitDirectory(NbMavenProjectImpl.java:713)
   at java.nio.file.Files.walkFileTree(Files.java:2677)
   at java.nio.file.Files.walkFileTree(Files.java:2742)
   at org.netbeans.modules.maven.NbMavenProjectImpl.getOtherRoots(NbMavenProjectImpl.java:695)
   at org.netbeans.modules.maven.classpath.MavenSourcesImpl.checkChanges(MavenSourcesImpl.java:164)
   at org.netbeans.modules.maven.classpath.MavenSourcesImpl.access$100(MavenSourcesImpl.java:101)
   at org.netbeans.modules.maven.classpath.MavenSourcesImpl$1.propertyChange(MavenSourcesImpl.java:123)
   at java.beans.PropertyChangeSupport.fire(PropertyChangeSupport.java:335)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:327)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:263)
   at org.netbeans.modules.maven.api.NbMavenProject.doFireReload(NbMavenProject.java:564)
   at org.netbeans.modules.maven.api.NbMavenProject.access$200(NbMavenProject.java:94)
   at org.netbeans.modules.maven.api.NbMavenProject$AccessorImpl.doFireReload(NbMavenProject.java:140)
   at org.netbeans.modules.maven.NbMavenProjectImpl$1.run(NbMavenProjectImpl.java:147)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1423)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2033)